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THE WONDERS OF GEOLOGY. Llct. VI. 



cocoa, pandanus, and other trees and plants, floated thither 

 by the waves, a soil on which they rapidly grow, and over- 

 shadow the white, dazzling surface. Trunks of trees, 

 drifted by currents from other countries, find here at length 

 a resting-place, and bring with them some small animals, as 

 lizards, insects, &c. Even before the trees form groves or 

 forests, sea-birds nestle there, and strayed land-birds find 

 refuge ; and at a still later period, Man takes possession of 

 the newly-created country. It is in this manner that the 

 Polynesian Archipelago has been formed. 



The immediate foundations of these islands are ancient 

 coral reefs, and some of these, in all probability, are based on 

 the cones or craters of submarine volcanoes long since extinct; 

 and others on the lofty peaks of a submerged continent 

 which has undergone a slow subsidence, and thus admitted 

 of the growth of successive generations of the coral-secreting 

 zoophytes, and the formation of immense beds and zones of 

 submarine coralline rocks. There is another circumstance 

 worthy of remark: most of these islands have an inlet 

 through the reef opposite to the large valleys of the neigh- 

 bouring land, whence numerous streams issue and flow into 

 the sea ; an easy ingress is thus afforded to vessels, as well 

 as the means of obtaining an abundant supply of fresh 

 water. 



Of the immense extent of the changes here contem- 

 plated, we may form some idea from the facts stated 

 by competent observers, that in the Indian Ocean, to 

 the south-west of Malabar, there is a chain of reefs and 

 islets 480 geographical miles in length ; on the east coast of 

 New Holland, an unbroken reef 350 miles long ; between 

 that and New Guinea, a coral formation which extends 

 upwards of 700 miles; and that Disappointment Islands 

 and Duff's Group are connected by 600 miles of coral 

 reefs, over which the natives can travel from one island to 

 another. 



